After days of struggling to figure out what was ailing former first lady Barbara Bush, doctors determined she was suffering a slight relapse of Graves' disease, a common form of hyperthyroidism. She left Methodist Hospital in Houston Wednesday morning, nearly five days after she checked herself in feeling ill. Symptoms of the disease usually include fatigue, sleeplessness, irregular heartbeats, and weight loss. The 84-year-old wife of former President George H.W. Bush was “alert, talkative and appeared to be getting stronger, ” according to a statement released by the hospital. It added that she is expected to make a full recovery.